When I'm using justified text with bigger than usual spaces between words, the cursor at the end of a word is placed too far to the right, making me think there is a space character there. So when I delete it, it actually removes the last letter of the word. Does anyone notice this problem?

Thanks for providing a sample and screenshot John. With them in hand I've been able to reproduce the confusing caret placement.

It seems the key factor is the font. The font "Times" triggers the undesirable caret placement, while "Time New Roman" does not. Are you able to switch fonts? I hope so, because it's unlikely we'll be able to do anything about this. Text justification is handled by the system (macOS) text engine. You can observe the same behavior in other apps (eg: Apple's TextEdit).